Baseline spleen size was recorded in all patients. The hematological and molecular responses were assessed at 3 and 6 months Dehydrodiisoeugenol respectively and thereafter at 6-monthly intervals. Long-term event free survival (EFS), transformation free survival (TFS), overall survival (OS) and adverse events were observed. Results Cumulative incidence of major MR (MMR) was 86% and deep MR (DMR ie MR 4.0 and MR4.5) was 39%. Early MMR and DMR after 6 months of therapy were achieved by 74.9% and 37% of patients, respectively. Two-year EFS, TFS and OS rates for all patients were 91.9%, 92% and Dehydrodiisoeugenol 92.3%, respectively. At median follow-up of 24 months, 81% and 49% of patients sustained MMR and DMR, respectively. The main adverse events were weight gain (4.6%) and abdominal pain (4%). Conclusion This study showed promising results in terms of achievement of early and sustained DMR in chronic phase CML, therefore, we recommend nilotinib as frontline treatment in Pakistani population. strong class=”kwd-title” Keywords: chronic myeloid leukemia, tyrosine kinase inhibitors, nilotinib, molecular response, Sokal Risk Score Background Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder characterized by the presence of breakpoint cluster regionabelson (BCR-ABL) oncoprotein that has markedly enhanced tyrosine kinase activity.1 Treatment outcomes Dehydrodiisoeugenol and survival rates for patients with CML in chronic phase have substantially improved with the emergence of tyrosine kinase inhibitors (TKIs).2,3The results of the International Randomized Study of Interferon and STI571 trial, comparing interferon vs imatinib, showed superior response rate and improved progression-free survival in the imatinib group, compared with previous standard therapy. However, long-term follow-up revealed failure to achieve a complete cytogenetic response (CCyR) in 18% of patients, loss of response i?10%, and intolerance to imatinib in 4%C8%.4 This led to the development of second-generation TKIs (nilotinib, dasatinib, and ponatinib), which are more potent inhibitors of BCR-ABL kinase activity.5 Nilotinib (Tasigna?) was found to be active against most imatinib-resistant mutations of BCR-ABL, except T315I, and induced durable CyRs in ~50% of patients in chronic phase CML when used as second-line therapy.6 Thereafter, nilotinib received US Food and Drug Authority approval for first-line treatment of CML, based on the results of the Phase III, multicenter, open-label, randomized trail Evaluating Nilotinib Efficacy and Safety in Clinical TrialsCNewly Diagnosed Patients (ENESTnd), which compared two different doses of nilotinib with standard dose of imatinib. The results of that trial revealed higher rates of major molecular response (MMR) with nilotinib compared with imatinib (71% with nilotinib 300 mg twice daily, 67% with nilotinib 400 mg twice daily, and 44% with imatinib).7,8 The Sokal risk scoring system is widely used to stratify risk in CML patients at baseline to predict the response to treatment and prognosis. Most of the studies have shown that at diagnosis, two-thirds of patients with chronic phase CML were in the low Sokal risk group. In a study by Cortes et al, in which nilotinib was used as frontline therapy in chronic phase CML, 70% of patients had a low Sokal risk score at diagnosis.9 Pakistan is a developing country and it has always been difficult to provide optimal health care to patients because of limited health resources. In Pakistan, imatinib and nilotinib are the only TKIs available for use. In most areas, imatinib is still being used as first-line treatment, with 65%C70% of patients achieving CCyR. This is believed to be the first study of CML patients from all over Pakistan to report the molecular response (MR) to nilotinib as front-line therapy in high, intermediate, and low Sokal risk patients. The aim of this study was to highlight the CD22 benefit of achieving early and sustained deep MRs (DMRs) with nilotinib, which are needed to achieve treatment-free remission and reduce the economic burden on health authorities. We also observed the number of adverse events with nilotinib and the improvement in overall survival (OS) and outcome of CML in our population. Patients and methods Patients This was an observational study conducted from March 2011 to June 2017. The study was approved by the Institutional Review.